KR0151304B1 - Lamp starting apparatus of lcd projector - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp starting apparatus of a liquid crystal projector in which instantaneous lighting / re-lighting of a lamp is concentrated by control of a starting pulse.

The present invention starts the lamp in consideration of the fact that the conventional liquid crystal projector is not instantaneous lighting and re-lighting, such as a TV environment, the start pulse conversion means for increasing the energy of the start pulse by changing the start pulse at the start of the lamp, the start And a start timing control means for controlling the start timing of the start pulse conversion means, and a DC drive timing control means for initially driving the lamp to DC and controlling the DC drive timing. By increasing the power supply, a large amount of energy can be supplied to the lamp at start-up, enabling instant lighting and re-lighting of the lamp, thus enabling the quick start of the liquid crystal projector and enabling the lamp to be turned on or off due to the lamp on / off failure. It prevents lamp life shortening and breakdown due to off-repetition. In other words, it is possible to display an image.

Description

Lamp starter of LCD projector

1A is a circuit diagram of a starter of a conventional liquid crystal projector.

(b) is a waveform diagram of each part of (a).

2 is a block diagram of a lamp startup device of a liquid crystal projector according to the present invention.

3 is a detailed circuit diagram of the present invention.

Figure 4 (a), (b) is an explanatory diagram of the pulse number and pulse width increase phenomenon according to the present invention and the conventional waveform comparison.

Figure 5 (a) is an external view of a typical metal halide lamp.

(b) is a diagram of path formation inside the lamp.

6 (a)-(f) are waveform diagrams of various parts of the present invention.

7 and 8 are another embodiment of the trial pulse variable portion of the present invention.

＊ Explanation of symbols on main parts of drawing

10: start and start pulse conversion section 11: start pulse variable section

20: start timing control unit 21, 31: switching control unit

30: DC drive timing control unit 30a: DC drive control unit

30b: timing controller 40: inverter section

50: lamp driver TR1-TR10: transistor

SD1: Thyristor PC1, PC2: Photo Coupler

T1, T2: Transformer VC1: Variable Capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector, and more particularly, to a lamp starting apparatus of a liquid crystal projector which enables instantaneous lighting and re-lighting of a lamp by controlling a start pulse.

Generally, a liquid crystal projector is a device for projecting light from a lamp and displaying an image signal input according to the projection of the light as an image on a screen, and FIG. 1 (a) schematically illustrates a circuit diagram of a starter of a conventional liquid crystal projector. As shown in the drawing, the resistor Ra and the capacitor Ca constituting the charging loop of the voltage source V _D are turned on when the charges charged in the capacitor Ca reach a predetermined voltage. And a transformer Ta that induces a voltage on the secondary side when switching the thyristors SDb, a diode Da and a capacitor Cb rectifying and smoothing the voltage induced on the secondary side of the transformer Ta, The auxiliary discharge tube SGa, which is turned on when the rectification and smoothing voltages of the diode Da and the capacitor Cb reach a predetermined voltage, and the transformer T2 which supplies a high voltage to the lamp LAMPO when switching the auxiliary discharge tube SGa. It consists of.

In the conventional lamp starter configured as described above, when the voltage of the node a becomes the breakover voltage of the thyristors SDa and SDb by the resistor Ra and the capacitor Ca at the time of starting. After the thyristors SDa and SDb are turned on, the charges charged in the capacitor Ca are discharged through the primary side of the transformer Ta and are discharged to the secondary side. Then, the diode Da and the capacitor Cb are discharged. Rectified and smoothed.

When the voltage rectified and smoothed by the diode Da and the capacitor Cb reaches a predetermined voltage (3KV), the auxiliary discharge tube SGa is turned on as the voltage is induced on the secondary side of the transformer Ta. The charge of the capacitor Cb is discharged through the primary side of the transformer Tb, and the high pressure of several tens of KV is induced on the secondary side of the transformer Tb by the turn ratio, and this high pressure peak pulse is supplied to the lamp LAMPO. To start the lamp.

At this time, the start of the lamp (LAMPO) is a high-voltage pulse induced on the vehicle side of the transformer (Tb) by the control of the break-over voltage of the thyristor (SDa), (SDb) and the turn ratio of the transformer (Ta), (Tb) The peak value was raised to control the start of the lamp LAMPO (FIG. 1 (b)).

However, when the lamp starter increases only the peak value of the start pulse of the lamp to drive the lamp, a large amount of energy cannot be supplied to the lamp.

In general, the liquid crystal projector system is currently driven by using a 150W ballast (Lamp and Ballast), but in the future HD (High Definition) or EWS (Engineering Workstation) type liquid crystal projector system using a ballast of 400W or more If the 150W and 400W lamps have a large internal pressure difference, the 400W has a much higher internal pressure than 1500W (the internal pressure must be high to generate more light).

If the internal pressure is high, more energy is required to start / restart the lamp. Therefore, only the peak value of the starting pulse is increased as in the conventional starter to start not only the current 150W but also any lamp having a higher internal pressure in the future. Since driving cannot supply much energy to the lamp, it is difficult to turn on and restart the lamp when the lamp is started.

In addition, users who are familiar with the TV environment can recognize that LCDs, which cannot be turned on or restarted, are displayed on the fly like a TV. When the camera is turned off, the image is not displayed immediately. As the user repeats the on / off, the life of the lamp and the set may be shortened and the failure may be caused.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to control a lamp starter of a liquid crystal projector which increases the energy of a start pulse by a change in impedance to facilitate the start of a lamp.

Another object of the present invention is to provide a lamp driving control circuit of a liquid crystal projector which allows the lamp to be started by controlling the start of the lamp to increase the internal temperature of the lamp so as to drive the lamp at any moment.

A characteristic of the present invention for achieving this object is a lamp for projecting light to the screen, and the start and start pulse conversion to increase the energy of the start pulse by starting the lamp and changing the lamp start pulse by a change in impedance at the start of the lamp A start-up timing control means for controlling the start-up timing of the start-up and start-pulse conversion means, and a DC drive timing control means for initially driving the lamp to DC and controlling the DC drive timing. Is in the device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a lamp starter of a liquid crystal projector according to the present invention, which starts a lamp LAMP1 and starts the lamp to increase the energy of the start pulse by changing the start pulse by a change in impedance during the start of the lamp LAMP1. And a start timing controller 20 for controlling the start timing of the start pulse converting unit 10, the start and start pulse converting unit 10, and a DC drive control unit 30a for initially driving the lamp LAMP1 to DC. ) And the DC drive timing controller 30 including the timing controller 30b for controlling the DC drive timing of the DC drive control unit 30a and the DC drive timing control of the DC drive timing controller 30. Inverter unit 40 driven by DC, the lamp driving unit 50 for driving the inverter unit 40 after the DC drive off of the initial lamp.

3 is a detailed circuit diagram of the present invention, wherein the start-up and start-up pulse converting unit 10 is connected to a base terminal between resistors R2 and R3 connected in series to a voltage source V _D , and is turned on at start-up. The switching transistor TR2 and the starting pulse variable part 11 which increases the peak pulse, pulse width, and number of pulses of the starting pulse when the transistor TR2 is turned on increase the energy of the starting pulse.

The starter pulse variable part 11 is connected to the collector terminal of the transistor TR1, so that the variable capacitance capacitor VC1, the variable capacitance capacitor VC1 and the inductance change also change the width and number of the start pulses. A resistor R4 connected between the voltage source V _D to determine the charging time constant of the variable capacitor VC1, and a bidirectional die having one end connected between the resistor R4 and the variable capacitor VC1. A transformer (T1) and a transformer (T1) in which a primary side (P1) is connected to the other end of the lister (SD1) and the bidirectional thyristor (SD1), and voltage is induced at the secondary side (P2) when the die Lister (SD1) is turned on. Diode (D1) and capacitor (C3), which are induced on the secondary side (P2) and rectify and stabilize the voltage, are turned on when the voltage rectified and smoothed by the diode (D1) and capacitor (C3) reaches a certain voltage. The secondary discharge tube SG1 and the capacitor C3 are connected in parallel to the primary side P1 and the secondary side P2 is connected to the RAM. It consists of a transformer T2 connected to the ramp LAMP1.

The start timing control unit 20 includes a switching transistor TR1 that is turned on during driving, one end of a collector terminal of the transistor TR1 is connected, and the other end of the transistor C1 is grounded. It consists of a switching control part 21 which controls switching timing.

The switching controller 21 includes a time constant voltage regulator R1 and a capacitor C1 connected in series with a voltage source Vcc, and a diode D1 having an anode terminal connected between the resistor R1 and a capacitor C1. And a zener diode ZD1 having a cathode connected to the cathode of the diode D1.

In addition, the DC drive control unit 30a of the DC drive timing controller 30 includes a switch transistor TR4 connected to a resistor R5 and R6 connected to a voltage source Vcc and turned on at start-up. The photo coupler PC1 and PC2 are turned on when the transistor TR4 is turned on. The timing controller 30 includes a switching transistor TR3 that is turned on during startup and a switching controller 31 that controls the switching timing of the transistor TR3.

The switching controller 31 includes a cathode at the resistor R1 and the capacitor C1, a diode D3 having an anode terminal connected between the resistor R1 and the capacitor C1, and a cathode of the diode D3. It consists of a Zener diode ZD2 connected with a stage.

In addition, the inverter unit 40 includes a transistor TR5-RT8 that operates as a push-pull to drive the lamp LAMP1, and the inverter unit 40 is ramped according to the output of the lamp driver 50 after startup. It drives (LAMP1), which is the same configuration as the conventional one.

According to the present invention configured as described above, the transistor TR2 is turned on according to the voltage supply as shown in FIG. 6 (b) by the resistors R2 and R3 at startup.

When the transistor TR2 is turned on, charging / discharging is performed by the charge / discharge of the variable capacitor VC1 and the resistor R4 as shown in FIG. 6C, whereby the voltage of the node a is a bidirectional thyristor. When the break-over voltage of SD1 is reached, the thyristor SD1 is turned on to discharge the charge charges into the variable capacitor VC1 through the primary side P1 of the transformer T1. A voltage of several KV peaks is induced on the secondary side P1 of Fig. 6) (Fig. 6 (d)).

The voltage induced on the secondary side P2 of the transformer T1 is rectified and smoothed by the diode D2 and the capacitor C3, whereby the auxiliary discharge tube SG1 is turned on to charge the capacitor C3. Is discharged through the primary side P1 of the transformer T2, a voltage of several tens of KV peaks is induced on the secondary side P2 of the transformer T2 (Fig. 6 (e)). Then, the high pressure pulse by the high pressure is supplied to the lamp LAMP1 to start the lamp LAMP1.

In this case, the lamp is driven by increasing only the peak value of the pulse as shown in FIG. 1 (b) by the break-over voltage of the thyristors and the turn ratio of the transformer. However, the present invention is directed to the variation of the capacitance of the variable capacitor VC1. The charge / discharge timing of the variable capacitor VC is increased to increase the number of pulses, thereby supplying more energy to the lamp LAMP1 to facilitate starting (FIG. 4 (a)).

In addition, by varying the capacitance of the variable capacitor capacitor VC1, the inductance with the transformer T1 is changed to increase the pulse width of the voltage induced on the secondary side P2 of the transformer T1, thereby transferring a large amount of energy to the transformer T2. By supplying more energy to the lamp (LAMP1) it is easy to start (Fig. 4 (b)).

On the other hand, it is driven after the lamp LAMP1 is started, but if the start is continued even during driving, the high-voltage pulse may affect other circuits, so that the start is blocked while being driven using the start timing controller 20.

That is, during driving after startup, the transistor TR1 is turned on and the transistor TR2 is turned on to terminate the startup. At this time, the transistor TR1 is terminated by the resistor R1, the capacitor C1, the diode D1, Zener diode (ZD1) is turned on after a certain time (about 1-3 seconds) turn-on delay so as not to affect the start-up. 6 (a) shows the voltage of the node d.

On the other hand, Figure 5 (a) shows the outline of the metal helide (Metal Helide) lamp, the lamp is a non-conductor state (initial) or when a pulse is applied to the path is formed between the electrode by the electron emission It is conductorized.

And when DC drive from (+) pole to (-) pole, a lot of hot electrons are discharged to (-) pole and a lot of energy is moved to the center (electrode), so a pass is easily formed and start is easily started. As a result, the path is gradually concentrated in the middle to facilitate starting (see Fig. 5 (b)).

That is, since the start-up is easy when the number of (-) pole electron emission of the lamp is increased and the temperature is increased inside the lamp, the present invention provides the lamp (LAMP1) by driving the lamp to DC during the startup time in the DC driving controller 30a. Start up.

At this time, the DC driving of the DC driving control unit 30a is a photo coupler PC1, as the transistor TR4 is turned on at the same voltage as in FIG. 6 (f) by the resistors R5 and R6 during the startup time. When PC2 is turned on, the transistors TR5 and TR6 are turned on by the voltages of nodes b and c as shown in FIG. To easily start the lamp LAMP1.

After the DC driving, the turn-on / turn-off time of the transistor TR3 is controlled by the resistor R1, the capacitor C1, the diode D3, and the zener diode ZD2, similarly to the transistor TR1. When TR3 is turned on, the transistor TR4 is turned off, DC is cut off, and the transistors TR5, TR6, TR7, and TR8 are alternately turned on / off by the lamp driver 50. The lamp LAMP1 is driven by AC, and the AC drive of the lamp LAMP1 is general, so the detailed description thereof is weak.

7 is a circuit diagram according to another embodiment of the starting pulse variable part 10 of the present invention. In the circuit of FIG. 3, the switching transistor TR9 switches the variable capacitor VC1 according to an external control signal. ), A capacitor C4 connected between the collector of the transistor TR9 and the resistor R4, and a capacitor C5 connected between the collector and emitter terminals of the transistor TR2, which is the transistor TR9. When the pulse width and the number of pulses of the starting pulse are varied by changing the inductances of the capacitors C4, C5 and the transformer T1 according to the turn on / turn off), the same parts as in the above embodiment are the same. Use the sign. That is, when the transistor TR9 is turned on by an external control signal at start-up, the charge is charged in the capacitor C4 and the charge is not charged in the capacitor C5.

Therefore, in this case, the pulse width of the voltage induced on the secondary side P2 of the transformer T1 is changed by the inductance between the capacitor C4 and the transformer T1, and the number of pulses by the capacitor C4 is changed. Is changed.

When the transistor TR9 is turned off by an external control signal during startup, electric charges are charged to the capacitors C4 and C5. In this case, the inductances of the capacitors C4, C5 and the transformer T1 are charged. The pulse width of the voltage induced on the secondary side P2 of the transformer T1 is changed.

The number of pulses is changed by the condensers C1 and C2, and the subsequent operation is the same as in the above embodiment, and thus will be omitted.

FIG. 8 is a circuit diagram according to another embodiment of the starting pulse variable part 11 of the present invention, between the die thruster SD1 and the primary side P1 of the transformer T1 in the circuit of the embodiment of FIG. A connected relay RL1 and a transistor TR10 for controlling the switching of the relay RL1 are further provided, which are inductances of the capacitors C4, C5 and the relays RL1 and T1. By the start pulse, the pulse width and the number of pulses are varied, and the same reference numerals are used for the same parts as in FIG. 7, and the operation is performed according to the turn-on / turn-off of transistors TR9 and TR10 as follows. The description will be divided into branches.

One). When transistors TR9 and TR10 turn on

When the transistors TR9 and TR10 are both turned on by an external control signal, the charge is charged to the capacitor C4, the charge is not charged to the capacitor C5, and the relay RL1 is turned on. The start pulse width is determined by the inductance of C4) and the transformer T1, and the number of start pulses is determined by the capacitor C4. Therefore, the starting pulse width and the number of pulses are increased by the condenser C4 and the transformer T1.

2) When transistor TR9 is turned on and transistor TR10 is turned off

When the transistor TR9 is turned on, the charge is charged to the capacitor C4 and the charge is not charged to the capacitor C5. Since the transistor TR10 is turned off, the relay RL1 is turned off so that the relay coil L _T. In this case, the start pulse width is determined by the inductance of the capacitor C4, the relay coil L _T and the transformer T1, and the number of start pulses is determined by the capacitor C4.

Therefore, the starting pulse width and the number of starting pulses are increased by the inductance of the condenser C4, the relay coil L _T and the transformer T1.

3). When transistor TR9 is turned off, transistor TR10 is turned on

When the transistor TR9 is turned off, charges are charged to the capacitors C4 and C5, and the relay RL1 is turned on when the transistor TR10 is turned on.

Therefore, in this case, the start pulse width is determined by the capacitors C4, C5 and the transformer T1, and the number of start pulses is determined by the capacitors C4 and C5. ) And the inductance of the transformer T1 increase the number and width of the starting pulses.

4). When transistors TR9 and TR10 are turned off

When the transistor TR9 is turned off, the capacitors C4 and C5 are charged. When the transistor TR10 is turned off, the relay RL1 is turned off so that current flows through the relay coil L _T. do.

Therefore, in this case, the starting pulse width is determined by the inductances of the capacitors C4 and C5 and the relay coil L _T and the transformer T1, and the number of starting pulses is determined by the capacitors C4 and C5. Therefore, the width and number of the start pulses are increased by the inductances of the capacitors C4, C5, the relay coil L _T , and the transformer T1.

Since the subsequent operation is the same as in the above embodiment, it is omitted.

As described above, the present invention increases the pulse peak value, the pulse width, and the number of pulses at the start of the lamp so that a large amount of energy can be supplied to the lamp at the start so that the instantaneous lighting and the re-lighting of the lamp can be performed at any moment such as a TV. In addition, the power can be turned on and off, and the liquid crystal projector can be started quickly.

In addition, it is possible to prevent shortening of lamp life and failure due to repeated on / off of the lamp due to on / off failure of the lamp.

Claims (11)

A lamp for projecting light onto a screen, starting and starting pulse converting means for starting the lamp and changing a lamp starting pulse by a change in impedance at the start of the lamp to increase the energy of the starting pulse, and the starting and starting pulse converting means And a start timing control means for controlling the start timing, and a DC drive timing control means for initially driving the lamp to DC and controlling the DC drive timing. According to claim 1, wherein the start-up and start-up pulse converting means is a switching transistor that is turned on at start-up, start-up pulse to increase the energy of the start-up pulse by increasing the peak value, pulse width, number of pulses of the start-up pulse when the transistor is turned on Lamp starter of the liquid crystal projector, characterized in that consisting of a variable portion. The variable capacitance capacitor of claim 2, wherein the starting pulse variable part is connected to the collector terminal of the transistor to change the width and number of the starting pulses, and is connected to one end of the variable capacitor capacitor and a voltage source. A resistor for determining the charging time constant of the capacitor, a bidirectional die lister connected to the other end of the resistor and the variable capacitor, and a primary side connected to the other end of the die lister, induce a voltage on the secondary side when the die lister is turned on. A diode and a capacitor for rectifying and smoothing the voltage induced on the secondary side of the first transformer, and a rectifying and smoothing voltage of the diode and the capacitor are constant by being connected to the secondary side of the capacitor and the first transformer. An auxiliary discharge tube that is turned on when a voltage is reached, and a primary side is connected in parallel to the capacitor and a secondary side is connected to the lamp; And a second transformer for supplying a starting voltage to the lamp by inducing a voltage on the secondary side when the auxiliary discharge tube is turned on. 3. The apparatus of claim 2, wherein the starting pulse variable part is connected in series with a switching transistor switched according to an external control signal and a resistor connected to a voltage source to determine the pulse width and number of the starting pulses according to the switching of the transistor. A first capacitor, a second capacitor connected between the collector and the emitter terminal of the transistor to determine the pulse width and the number of starting pulses according to the switching of the transistor, and one end connected between the resistor and the first capacitor. A diode that rectifies and smoothes a thyristor, a first transformer having a primary side connected to the other end of the thyristors, and voltage induced on the secondary side when the thyristors are turned on, and a voltage induced on the secondary side of the first transformer; Connected to the secondary side of the capacitor, the capacitor and the first transformer, and the rectification and smoothing voltages of the diode and the capacitor And an auxiliary discharge tube which is turned on upon reaching, and a second transformer for supplying a starting voltage to the lamp when the secondary voltage of the first transformer is induced. The method of claim 2, wherein the start pulse variable part is connected to a first and second transistors for switching according to an external control signal, and is connected to a voltage source to determine the number of pulses and the pulse width of the start pulse according to the switching of the first transistor. A second capacitor connected between the collector and the emitter terminal of the transistor to determine the number of pulses and the pulse width of the starting pulse according to the switching of the first transistor, and one side end between the resistor and the first capacitor. The connected thyristor, one side of which is connected to the diester, a relay which is turned on when the second transistor is turned on to determine a pulse width of a start pulse, and a primary side of which is connected to the relay, so that A first transformer into which a voltage is induced, a diode and a capacitor to rectify and smooth a voltage induced on a secondary side of the first transformer, and An auxiliary discharge tube connected to the secondary side of the capacitor and the first transformer and turned on when the rectification and smoothing voltages of the diode and the capacitor reach a constant voltage, and supplying a starting voltage to the lamp when the secondary side voltage of the first transformer is similar. A lamp starting device for a liquid crystal projector, comprising a second transformer. The switching timing control device of claim 1, wherein the start timing control means includes a switching transistor that is turned on during startup, a capacitor connected at one end to a collector end of the transistor and grounded at the other end, and controlling a switching timing of the transistor. Lamp starter of the liquid crystal projector, characterized in that consisting of a switching control unit. The LCD driving lamp of claim 1, wherein the DC driving timing controller comprises a DC driving controller for initially driving the lamp to DC, and a timing controller for controlling the DC driving timing of the DC driving controller. Device. 8. The DC driving controller of claim 7, wherein the DC driving controller comprises a switching transistor having a base connected between a resistor connected to a voltage source and being turned on at startup, and first and second photo couplers turned on when the transistor is turned on. Lamp starter of liquid crystal projector. 8. The lamp startup apparatus of claim 7, wherein the timing controller comprises a switching transistor that is turned on during startup and a switching controller for controlling switching of the transistor. 10. The switching controller according to claim 6 or 9, wherein the switching controller comprises: a time constant adjusting resistor and a capacitor connected in series to a voltage source, a diode having an anode end connected between the resistor and the capacitor, and a cathode end of the diode. A lamp starting device for a liquid crystal projector, characterized by comprising the connected zener diodes. The method of claim 1, further comprising an inverter means for driving the lamp DC according to the output of the DC drive timing control means, and a lamp driving means for driving the lamp by driving the inverter means after the lamp is started. Lamp starter of liquid crystal projector.